Max voltage for R9 390?

[steffeeh]

Asking for a friend, who has an R9 390 and he wants to give it some overclocking.

I don't have any experience owning AMD graphics cards, so I don't know how high you can go with the voltage. I know on Nvidia cards the max voltage is hard capped, so you just shove the overvolt to the max and then start dialing in the overclock.
However how does it work with AMD cards? Do they also have a hard cap in a safe enough region, or is there a max voltage not to exceed for everyday use?

Assuming thermals are good that is.

 

[Compuser10165]

Asking for a friend, who has an R9 390 and he wants to give it some overclocking.

I don't have any experience owning AMD graphics cards, so I don't know how high you can go with the voltage. I know on Nvidia cards the max voltage is hard capped, so you just shove the overvolt to the max and then start dialing in the overclock.
However how does it work with AMD cards? Do they also have a hard cap in a safe enough region, or is there a max voltage not to exceed for everyday use?

Assuming thermals are good that is.

I also have an MSI Gaming R9 390 (1060mhz core and 1525 memory in factory OC mode) and I OCed it, so I am more than qualified to answer this question. It depends a lot on sillicon lottery but there is a general limit for all (for R9 390/R9 390X under 1200mhz (more like under 1180mhz) on the core and ~1750mhz on the memory). As opposed to Nvidia you can increase the clock on AMD by a single Mhz (not in steps) so you can get much more granular. An R9 390 already has a chip that is very close to its limits (thermally and architecturally) so increasing the voltage very much will not do very much to help with the OC but will increase the temps significantly (sometimes even more than 15C-20C). I keep my R9 390 at 1100mhz on the core and 1600mhz on the memory with +35% power limit and no added voltage (I use MSI Afterburner).

Without adding additional voltage I can get to 1104mhz on the core stably. If I increase the voltage by 19mv I can get to 1120mhz but sometimes I get artifacts (as it is not completely stable). By increasing the core voltage to +100mv and power limit +50% I've been able to get a Valley run at 1140mhz (still some artifacts). By that time, temps were around 86C with the side panel open (for better airflow). So I concluded that OCing further is not worth the extra power and temperature (also it could hurt your gpu in the long run pushing it this close to its limits).

To sum up, a good OCing R9 390 will hit 1140mhz with not so much added voltage (maybe 1160 but it's better to run it stably and with lesser voltage). A bad OCing R9 390 may not even be able to hit 1080Mhz no matter the voltage. You just have to take your time tuning to truly know your gpu potential. Don't get scared by a couple of freezes or crashes, it's just how OC should be done.